title: Structural identification of novel glucoside and glucuronide metabolites of (-)-epigallocatechin-3-gallate in mouse urine using liquid chromatography/electrospray ionization tandem mass spectrometry.
abstract: (-)-Epigallocatechin-3-gallate (EGCG), the most abundant and most biologically active polyphenolic compound in tea, has been proposed to have many health beneficial effects. The metabolic fate of EGCG, however, is not well understood. In the present study, we identified a novel EGCG metabolite, 7-O-beta-D-glucopyranosyl-EGCG-4''-O-beta-D-glucupyranoside, in a mouse urine sample using liquid chromatography/electrospray ionization tandem mass spectrometry. The structure of this metabolite was confirmed by analyzing the MSn (n = 1-4) spectra as well as comparing the MS/MS spectra of its product ions with those from EGCG and EGCG-4''-O-beta-D-glucupyranoside standards. To our knowledge, this is the first report of the identification of a glucoside metabolite of EGCG in mammals. Our results indicate that glucosidation represents a novel pathway in the metabolism of EGCG in mice.
authors.affiliation: Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, 164 Frelinghuysen Road, Piscataway, NJ 08854-8020, USA. ssang@nccu.edu
authors.forename: Shengmin
authors.initials: S
authors.lastname: Sang
authors.forename: Chung S
authors.initials: CS
authors.lastname: Yang
mesh_terms: D000818:Animals; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000652:urine; D002853:Chromatography, Liquid / Q000379:methods*; D005960:Glucosides / Q000737:chemistry* / Q000652:urine; D020719:Glucuronides / Q000737:chemistry* / Q000652:urine; D008297:Male; D051379:Mice; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry
chemical_list: D005960:Glucosides; D020719:Glucuronides; D002392:Catechin; C045651:epigallocatechin gallate